Don't forget that Valium has metabolites with a half-life of like 200 hours. That's why habituation can develop even with a fairly infrequent administration. Ambien is also a "GABA-ergic" but the half-life is really short. Therefore you aren't messing with the GABA system round the clock.
I think you should mess with the GABA system as little as possible. IMO it's better to go with stuff like Trazadone, Propiomazin (I use this, not habit forming), Hydroxyzine, diphenhydramine or even Remeron before going the benzo route.
you might be thinking of clonazepam but valium certainly doesnt have effects that long, nor does it cause binding for that long. using them twice a week is perfectly fine, i would only be worried about clonazepam or xanax xr, not diazepam.
benzos are gaba a receptors agonists, ambien is a non benzodiazipine gaba b receptor agonist. gabatril might be worth looking in too. all benzos make sleep quality shit. your other advice is solid, but diphenhydramine fucks rem sleep to hell, so only as needed.
